Late on Tuesday, the US Circuit Court of Appeals upheld a ruling handed down by US District Judge Lucy Koh in San Jose that allowed the workers to sue as a group. The group could seek as much as $9 billion in damages.

The accused companies appealed the ruling, saying that the claims were too disparate, because they involved employees with 2,400 job titles at seven companies, and that the plaintiffs were not claiming that the total hiring of employees was affected.

The legal battle between Silicon Valley workers and the seven tech companies began in 2011, with five software engineers suing them, alleging “overarching conspiracy” to fix wages by agreeing not to hire each others’ employees. The case was mostly built on emails between top executives including former Apple CEO Steve Jobs and ex-Google Chief Eric Schmidt.